Relationship between surgeon volume and adverse outcomes after RYGB in Longitudinal Assessment of Bariatric Surgery (LABS) study

BackgroundBariatric surgery is technically demanding surgery performed on high-risk patients. Previous studies using administrative databases have shown a relationship between surgeon volume and patient outcome after Roux-en-Y gastric bypass (RYGB). We examined the relationship between surgeons' annual RYGB volumes and 30-day patient outcomes at 10 centers within the United States.MethodsThe Longitudinal Assessment of Bariatric Surgery (LABS)-1 is a prospective study examining the 30-day adverse outcomes after bariatric surgery. The outcomes after RYGB were adjusted by procedure type (open versus laparoscopic), functional status, body mass index, history of deep vein thrombosis, pulmonary embolism, and obstructive sleep apnea. The data were examined to determine the nature and strength of the association between surgeon volume and patients' short-term (30-day) adverse outcomes after RYGB.ResultsThe analysis included 3410 initial RYGB operations performed by 31 surgeons, 15 of whom averaged <50 cases annually. The crude composite adverse outcome (i.e., death, deep vein thrombosis, pulmonary embolism, reintervention or nondischarge at day 30) incidence was 5.2%. After risk adjustment, a greater surgeon RYGB volume was associated with lower composite event rates, with a continuous relationship (i.e., varying cutpoints differentiated the composite event rates), such that for each 10-case/yr increase in volume, the risk of a composite event decreased by 10%.ConclusionIn the LABS, the patient's risk of an adverse outcome after RYGB decreased significantly with the increase in surgeon RYGB volume (cases performed annually).     

Novel substrates

Enteral and parenteral feeds need at least to contain adequate amounts of water, energy, protein, electrolytes, vitamins and trace elements. Ready-manufactured parenteral feeds for example are incomplete because of shelf-life constraints and require the addition of vitamins (especially) and trace elements. Acute vitamin deficiencies, notably thiamine deficiency, can be precipitated if this is not adhered to. An increasing interest, however, exists in the use of feeds containing substrates, which are intended to improve patient outcome in particular clinical circumstances. The purpose of this article is to examine as to what is available and make recommendations on their use. It deals with artificial feeds only - disease-specific diets are outside our remit.     

Effect of caffeine on superior mesenteric artery blood flow velocities in preterm neonates

Objective: To investigate the effect of caffeine infusion on superior mesenteric artery (SMA) blood flow velocities (BFV) in preterm infants.

Methods: Prospective observational study on 38 preterm neonates 28–33⁺⁶ weeks gestation, who developed apnea on their first day of life, and caffeine citrate infusion was initiated at a loading dose of 20?mg/kg, followed by a maintenance dose of 5–10?mg/kg/day. Duplex ultrasound measurements of SMA BFV were recorded: peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI), at 15?min before, 1-, 2- and 6-h after caffeine loading dose, and 2?h after two maintenance doses.

Results: There was a significant reduction in PSV 1-h (p?=?.008), a significant decrease in EDV 1- and 2-h (p?=?.000 and p?=?.005, respectively) and a significant increase in RI 1- and 2-h (p?=?.003 and p?=?.005, respectively) following caffeine loading dose, as compared to values before caffeine infusion. No significant effect of caffeine maintenance doses on SMA BFV was observed (p?>?.05).

Conclusion: Blood flow in SMA is significantly reduced after caffeine citrate infusion at a loading dose of 20?mg/kg. This effect continues for at least 2?h. Meanwhile, SMA BFV seems not affected by maintenance doses.     

Hemodynamic effects of carvedilol infusion and the contribution of the sympathetic nervous system in rats with heart failure

We investigated the contribution of the sympathetic nervous system (SNS) in maintaining the blood pressure and in regulating the cardiac function during and after carvedilol administration in rats with heart failure (group F). Left ventricular end-diastolic pressure, percent functional shortening, and rates of intraventricular pressure rise were significantly changed by carvedilol infusion as compared with the basal values in group N (normal rats), but not in group F. The left ventricular end-diastolic pressure was elevated, corresponding to the enhancement of the plasma norepinephrine (NE) concentration caused by carvedilol infusion, in group N. The enhancement of the plasma NE concentration induced by carvedilol administration in group F was higher than that in group N. The value for the maximal hypertensive effect of NE intravenous infusion (Emax) was decreased, and the plasma NE concentration at half-maximal effect (EC50) was increased in group F as compared with the values in group N. These results indicate that the SNS (presynaptic) activity is increased and that the SNS receptor sensitivity in the cardiovascular regulation system is decreased in heart failure.     

Signaling mechanisms mediated by G-protein coupled receptors in human platelets

AIM: The present study deals with the investigation of mechanisms involved in the synergistic interaction between epinephrine and arachidonic acid (AA). METHODS: Venous blood was taken from healthy human volunteers reported to be free of medications for one week. Platelet aggregation was monitored at 37 ℃ using Dual-channel Lumi-aggregometer. The resulting aggregation was recorded for 5 min by the measurement of light transmission as a function of time. RESULTS: The data show that a synergism in platelet aggregation mediated by subthreshold concentrations of epinephrine (1 μmol/L) and AA (0.2 μmol/L) was inhibited by the α2-receptor antagonist(yohimbine, IC50=0.6 μmol/L) and an inhibitor of AA-cyclooxygenase (COX), indomethacin (IC50=0.25 μmol/L).In examining receptor influence on intraplatelet signalling pathways, it was found that the synergistic effect was inhibited by calcium channel blockers, verapamil (IC50=0.4 μmol/L) and diltiazem (IC5o=2.5 μmol/L), as well as by low concentrations of inhibitors of phospholipase C (PLC) (U73122; IC5o=0.2 μmol/L) and mitogens activated protein kinase (MAPK) (PD 98059; IC5o=3.8 μmol/L). Herbimycin A, a specific inhibitor of tyrosine light chain kinase (TLCK), showed inhibition at IC5o value of 15 μmol/L, whereas chelerythrine, a protein kinase C (PKC)inhibitor, had no effect up to 20 μmol/L. CONCLUSION: These data suggest that synergism between epinephrine and AA in platelet aggregation is triggered through receptors coupled to G-protein, which in turn, activate PLC,COX, and MAP kinase-signaling pathways.     

Betaxolol improves the survival rate and changes natriuretic peptide expression in rats with heart failure

Growing evidence suggests that the autoimmune mechanism plays an important role in the pathogenesis of dilated cardiomyopathy. The purpose of this study was to evaluate the effect on the cardiac structure and function by the transfer of immunoglobulin G (IgG) and/or lymphocytes from rabbits immunized with a synthetic peptide corresponding to the sequence of the second extracellular loop of beta1-adrenoceptor (beta peptide) into severe combined immunodeficiency (SCID) mice. CB-17 SCID mice were injected intraperitoneally with 2 mg of IgG and/or 1 x 10(7) peripheral blood lymphocytes (PBL) from either rabbits immunized with both beta1 peptide and adjuvant (beta group), and adjuvant or rabbits with adjuvant only (N group). Thirty-five SCID mice were divided into seven groups: (1) N-IgG group; (2) N-PBL group; (3) N-IgG+PBL group; (4) beta-IgG group; (5) beta-PBL group; (6) beta-IgG+PBL group; and (7) control group. Morphological, serological and endocrinological studies were performed 70 days after the transfer. Results showed that heart weight and heart weight/body weight ratio in the beta-IgG+PBL group tended to be increased as compared with those in other groups. All mice in the beta-IgG group, two in the beta-PBL group and four in the beta-IgG+PBL group showed high titer of rabbit anti-beta1-adrenoceptor antibodies. Brain natriuretic peptide in the beta-IgG+PBL group showed a significant increase as compared with those in the control group and N-IgG+PBL. Pathohistologically, focal infiltration of inflammatory cells in the myocardium was observed in one mouse of the beta-IgG+PBL group. Rabbit CD3-positive T-lymphocytes in the myocardium were observed in two mice of the beta group. In conclusion, transfer of IgG and PBL from rabbits immunized with beta1 peptide was able to induce the early stages of myocardial damage in SCID mice. These data provide direct evidence that the autoimmune mechanism is important in the pathogenesis of dilated cardiomyopathy.     

Urinary retinol excretion in children with acute watery diarrhoea

Children with diarrhoea due to rotavirus infection excrete retinol in urine. This study aimed at demonstrating the extent and mechanism of urinary retinol excretion in children with acute watery diarrhoea caused by pathogens other than rotavirus. Thirty-two children, aged five months to five years, hospitalized with watery diarrhoea predominantly due to enterotoxigenic Escherichia coli in Bangladesh, were studied. Their serum retinol and retinol-binding protein (RBP) were low at admission and increased significantly after recovery from illness. The mean hospital stay of these patients was four days. Forty-seven percent of the children excreted retinol in urine on day 1, and about 38% continued excreting retinol on day 3. The estimated urinary retinol loss of 3.44 micromol for the illness episode represented more than 40% of liver retinol reserve (8.25 micromol) in malnourished children. A conservative estimate of the loss would represent at least 20% of the liver reserve in relatively better-nourished children. Kidney tubular dysfunctions of increased RBP excretion significantly predicted urinary retinol excretion in children with watery diarrhoea.     

A randomized, placebo-controlled trial of the effect of zinc supplementation during pregnancy on pregnancy outcome in Bangladeshi urban poor

BACKGROUND: Maternal zinc supplementation has been suggested as a potential intervention to reduce the incidence of low birth weight in developing countries. To date, placebo-controlled trials have all been performed in industrialized countries and the results are inconsistent. OBJECTIVE: The objective of this study was to evaluate whether zinc supplementation in Bangladeshi urban poor during the last 2 trimesters of pregnancy was associated with pregnancy outcome. DESIGN: We conducted a double-blind, placebo-controlled trial in which 559 women from Dhaka slums, stratified by parity between 12 and 16 wk of gestation, were randomly assigned to receive 30 mg elemental Zn/d (n = 269) or placebo (n = 290). Supplementation continued until delivery. Serum zinc was estimated at baseline and at 7 mo of gestation. Dietary intake was assessed at baseline and anthropometric measurements were made monthly. Weight, length, and gestational ages of 410 singleton newborns were measured within 72 h of birth. RESULTS: At 7 mo of gestation, serum zinc concentrations tended to be higher in the zinc-supplemented group than in the placebo group (15.9 +/- 4.4 compared with 15.2 +/- 4.3 micromol/L). No significant effect of treatment was observed on infant birth weight (2513 +/- 390 compared with 2554 +/- 393 g; NS) or on gestational age, infant length, or head, chest, or midupper arm circumference. The incidence and distribution of low birth weight, prematurity, and smallness for gestational age also did not differ significantly after zinc supplementation. CONCLUSIONS: Supplementation with 30 mg elemental Zn during the last 2 trimesters of pregnancy did not improve birth outcome in Bangladeshi urban poor. These results indicate that interventions with zinc supplementation alone are unlikely to reduce the incidence of low birth weight in Bangladesh.     

Effects of eplerenone, a selective aldosterone blocker, on the progression of left ventricular dysfunction and remodeling in rats with dilated cardiomyopathy

Aldosterone blockade reduces morbidity and mortality in patients with heart failure. We studied the effects of eplerenone, a novel aldosterone blocker, on the progression of left ventricular dysfunction and remodeling in rats with dilated cardiomyopathy after autoimmune myocarditis. Twenty-eight days after immunization, the surviving Lewis rats were randomized to 1 month's oral treatment with low-dose eplerenone (group L), high-dose eplerenone (group H) or vehicle (group V). Five of 15 (33%) rats in group V and 3 of 15 (20%) rats in group L died during the course of treatment. High-dose eplerenone significantly reduced cardiomyocyte hypertrophy, heart weight and heart weight to body weight ratio. Eplerenone improved left ventricular function in a dose-dependent manner. Central venous pressure and left ventricular end-diastolic pressure were lower, and +/-dP/dt and fractional shortening were higher in group H than group V. Eplerenone also attenuated myocardial fibrosis and reduced left ventricular mRNA expressions of TGF-beta(1) and collagen-III. Our results indicate that treatment with eplerenone improved left ventricular dysfunction and attenuated left ventricular remodeling in rats with heart failure.